XAircraft Xcope Pro

[Quadrocoptregic]

Hi all,

Thought some of you might be interested to see what I did with my Xcope, it's essentially done except for calibrating the GPS and taking her on the maiden.

Now I can finally start building-out my X650 Pro...

Any comments, criticism, etc. welcome, especially if you see something wacky ('cuz I'm a n00b).

Still trying to figure-out how to easily, securely and reliably mount the GoPro on this gimble and still use the LayerLens. Might have to try a lens guard (from RMRC I think) instead.

Thanks and top o' the season!

 

[Quadrocoptregic]

Hi all,

Took her out for her first flights today, it flew. GPS ATT mode seems pretty fickle, sometimes it locks and other times it just wanders off like it needs trimming? Wierd.

Failsafe worked flawlessly. Vibration always under .3 and .5 under harder throttle input

However, I am having a few issues and was hoping someone cold comment.

Curious to know if it's normal (or not) to have 2 motors' outputs 10%-15% greater than the other two? M2 and M4 are outputting consistently higher than M1 and M3?

Getting some strange, subtle higher-frequency oscillation in flight, like one of the motors is continually trying to compensate for something and the gain is too high or something. Already had to turn down my gains to .9 in SuperX and that helped but still not altogether smooth.

Was flying it with the "Xcope" type chosen in SuperX but I think I'll try "Quad" next time.

Only getting about 6 minutes in the air on a 5000mah Turnigy 20C, 16.7v down to 15v, which I'm not impressed about as it's mostly hovering. This is with an EzOSD, 600TVL camera and 600mW A/V transmitter running.

Regardless, are these batteries crap or why am I getting such rapid drain? Should be getting more time than that should I not?

Anyway, came home in one piece and reasonably satisfied with that and some fun maiden videos off the GoPro.

Would sure appreciate any help if anyone can comment or criticize.

Thanks very much!

 

[SleepyC]

I used to have a SuperX rig that weighed more than that with 740KV Tmotors spinning 12" props and on a 6000 mAh 4S pack I'd get 12 - 13 minutes!

And my motors would usually vary about 10 - 13%

Here was the pig... it was heavy but flew GREAT!

View attachment 22093

 

[econfly]

Curious to know if it's normal (or not) to have 2 motors' outputs 10%-15% greater than the other two? M2 and M4 are outputting consistently higher than M1 and M3?

Getting some strange, subtle higher-frequency oscillation in flight, like one of the motors is continually trying to compensate for something and the gain is too high or something. Already had to turn down my gains to .9 in SuperX and that helped but still not altogether smooth.

Was flying it with the "Xcope" type chosen in SuperX but I think I'll try "Quad" next time.

Only getting about 6 minutes in the air on a 5000mah Turnigy 20C, 16.7v down to 15v, which I'm not impressed about as it's mostly hovering. This is with an EzOSD, 600TVL camera and 600mW A/V transmitter running.

Regardless, are these batteries crap or why am I getting such rapid drain? Should be getting more time than that should I not?

Anyway, came home in one piece and reasonably satisfied with that and some fun maiden videos off the GoPro.

Would sure appreciate any help if anyone can comment or criticize.

Thanks very much!

Nice looking rig.

M2/4 spinning more than M1/3 probably implies imbalance with respect to yaw. Check motor mounts and confirm all are mounted level to the horizontal axis (or to the same offset, counter one way, clockwise the other). Also check arms are level or equal in bias up/down. Most likely one of the mounts is slightly twisted. Just checked your photos again and note (maybe) different arm lengths front to back. In this case, weight imbalance could produce the yaw imbalance.

Can't say much about battery drain without knowing details like weight, motor specs, prop size, etc.

 

[Quadrocoptregic]

Nice looking rig.

M2/4 spinning more than M1/3 probably implies imbalance with respect to yaw. Check motor mounts and confirm all are mounted level to the horizontal axis (or to the same offset, counter one way, clockwise the other). Also check arms are level or equal in bias up/down. Most likely one of the mounts is slightly twisted. Just checked your photos again and note (maybe) different arm lengths front to back. In this case, weight imbalance could produce the yaw imbalance.

Can't say much about battery drain without knowing details like weight, motor specs, prop size, etc.

Thanks a lot for the reply and thank-you too SleepyC!

Turns-out two of my motor mounts were loosened enough to move slightly on the arms. Have since re-tightened with more blue locktite and tried to level motors/mounts/props as much as possible, prop blade tip to blade tip of adjacent prop, etc. Hopefully that will help.

The AUW of the quad is about 2050 grams +/- 10 or 15 grams, T-motor P7001 X650 Pro motors (800kv versions of the MN3110), T-motor 30A ESCs and T-motor 11x3.7 CF props.

Thanks very much for your help, I think you were bang-on with your advise and suggestions. If the few specs I provided help you assess my battery drain I look forward to hearing from you again.

Cheers!

 

[econfly]

Glad to help.

Based on the motor specs I see online and your props and AUW I would guess the rig is pulling around 20 amps at hover (assuming 4s source). You should be able to get 4 amp hours out of a 5000 mAh battery safely, and that means you should get something like 4 Ah / 20A * 60 min/h = 12 minutes of flight time. All very rough of course. If you can, measure what you are putting back into the battery. It should be about 4 amp hours -- i.e., 4000 mAh. If it is, your 6 minutes of flight time is way low and the battery is not doing the job it should. If, on the other hand, you are only putting, e.g., something around 2000 mAh back into the battery to fully charge it then you probably can safely extend flight time and take the battery down a bit more.

 

[Quadrocoptregic]

Thank-you very much econfly!

I'll put your advice to work again and see what happens.

So if I can't get upwards of 4000mah out of these packs without crashing my battery packs are crap?

My battery packs come off full charge very quickly and then lessen gradually according to Black Box data. Intuitively I would think this voltage decline should be more linear, especially given mostly hovering flight? Very curious about this also if you can comment.

Is this normal battery behavior, LIPOs themselves are still a bit of a mysterious beast to me?

You answered a question I have had but had not asked also in terms of how many mah a 5Ah battery can safely supply without dropping voltage too low and crashing a quad.

It's odd that there is not a different "system" of mounting these arms and motor mounts, just holes drilled in the limbs at supposedly 90* to each other. There is play in some of these holes and I swear some of them are not exactly 90* opposed on some limb ends. Making sure motors and props are level is not in any instructions but it's so important for good performance.

If nobody minds, I'll keep posting my results as not only a travelog of what is a huge adventure for an old codger but in hopes that this stuff is useful to someone else.

Thanks again econfly, top o' the season to you and yours.

 

[econfly]

Keep posting your results. This hobby is a never-ending learning experience for all of us.

Lipos are like any battery in that a load will result in lower voltage. So, when you first start the copter and take off the voltage will immediately drop from about 4.2v/cell (full charge) to something very noticably lower. The amount of drop depends on the battery and the load. Following that you can expect heavier voltage drops early in flight and then more gradual voltage drops later.

Everyone wants to know when they should stop flying based on observed voltage. That's hard to answer because it depends on the load and the battery, so practical experience is usually the best guide. The general rule for lipos is to keep the unloaded voltage at or above 3.6v/cell. The problem is that in flight you have a load on the battery so the observed voltage can easily be under 3.6v/cell. For 4s power, as in your case, at-rest voltage should be at least 4 x 3.6 = 14.4 v. My guess is your battery is fine, and that you can safely entend flight to at least 10 minutes.

The most practical way to know how much charge you are using is to measure the energy it takes to re-charge the battery (this isn't technically correct, but it's close enough). As I mentioned, another lipo general rule is that you can get about 80% of the rated power out of the battery without damaging it. I often push that to 90% and just accept that my batteries will fail sooner as a result. It's a judgment call. When the battery won't take a full charge or puffs up you know you went too far. Once that happens the battery is done for good, so careful incremental testing is the safest and most economical option.

 

[Quadrocoptregic]

You're being a huge help, thanks.

Went out to test your my work today and had mixed results.

Flew from 16.7v down to 15.2v loaded (battery alarm set to 3.8v) and 15.7v resting. Got over 5 minutes again.

So the question still is why am I drawing so much amperage just hovering?

Then got a bit cocky playing with my mode switch too close to the ground and dinged-up all my props, broke a couple of my limb retainer clips and knocked my two rear motor mounts loose. Got off really lucky for my stupidity and just another couple of bucks and a bit of wrenching should do it. This thing is not well balanced at all and did not self-level in Attitude mode from the brief time I tried.

Now that I've destroyed my props essentially and learned a couple of valuable lessons I'm going to get a set of 12x4.0s for it and try those. Maybe the propulsion will more than cancel the bit of extra torque needed to turn them?

Charged one pack from 14.8v-16.8v @4A (just to keep the math simple) and it took almost 68minutes. My charger indicated 4118 "charged capacity" which I can only assume is a value in mah from discharged state to charged state for that charge. The instruction manual for my HiTec charger is crap. So the battery seems to be working fine.

When I get it in the air again I'll definitely put your advice to work and take the battery into further discharge (safely of course) and put some times on those flights to see if I can't get to 10 minutes at least.

Thank-you very mach econfly!

 

[econfly]

Again, happy to help. I've trashed a few props myself! Not sure about 12x4 props on a 800kv motor with 4s. I would check the motor specs to confirm -- that's a pretty aggressive prop for the motor size and RPM.

 

[X650Mouse]

Again, happy to help. I've trashed a few props myself! Not sure about 12x4 props on a 800kv motor with 4s. I would check the motor specs to confirm -- that's a pretty aggressive prop for the motor size and RPM.

I have XA X650 Pro the motors are same KV close enough, I think about 11k rpm I run 4S and T-Motor (CF) prop 12x4 the default from XA is 11x4.7 the 12's are great and would not replace them although very expensive

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